Turbine construction

ABSTRACT

A turbine having a casing provided with an inwardly projecting partition equipped in turn with a rearwardly extending section terminating in a flange, a shroud ring having a forwardly extending portion underlying the rearward section of the partition is equipped with a flange at its rearward end for connection to the flange on the partition.

United States Patent [191 Shulock I TURBINE CONSTRUCTION i 1 1 3,724,969 1 Apr. 3, 1973 [54] FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Charles Shulock, Jeannette, Pa. 572,859 10/1945 Great Britain AIS/219 [73] Assignee: Carrier Corporation, Syracuse, NY. I

FIIed: Nov, 1, ima y F. RaduaZo 2 APPL 194 1 3 Attorney-Harry G. Martin,.lr. et a].

52 U.S. Cl'...; ..-...4l5 190 415 199,415 219, Y i 1 v I I 415/1201 57 ABSTRACT [51] Int. Cl. ..F0ld 1/02, FOld 25/24, FOld 25/26 turbine having a casing provided with an inwardly [58] Field of Search ..4l5/189, 190, 193, 194, 199, p j ting par iti n quipp d in turn with a rearwardly 41 5 2 91 136,108 extending section terminating in a flange, a shroud a ring having a forwardly extending portion underlying the rearward section of the partition is equipped with [56] I References a flange at its rearward end for connection to the UNITED STATES PATENTS "W pamuon' 2,796,231 6/1957 11ml ..-......4l5/|94 2 Claims, 3 Drawing Figures H pk l g g La l9 18 22 as I g; g g

. 29 i1 1a 40 as j PATIENTEWR 3 I975 sum 2 OF 2 :5 Loi TURBINE CONSTRUCTION BACKGROUND OF THE INVENTION Steam powered turbines incorporating a plurality of stages of blading are often employed for the purpose of generating electric power by mechanically connecting an electric generator to the power shaft of the turbine. Turbines of the type described are also used for driving gas compressors under circumstances where the supply of steam represents an economical source of power.

Steam at relatively high pressure and temperature enters the turbine casing and is directed through an annular passage extending axially of the machine to an outlet formed in the casing. The annular passage is provided with a plurality of blades arranged so that when engaged by the supply of steam rotary motion is imparted to a shaft upon which the blading is mounted.

In order toobtain as high an order of efficiency as possible the temperature of the steam entering the turbine is elevated to as high a level as possible. As the steam passes through the turbine it flows through consecutive rows of blading, causing the blades attached to the rotor or output shaft to rotate. The rotation of the turbine shaft is accomplished by extracting kinetic energy from the steam, resulting in a lowering of the temperature'and pressure of the steam. Thus, the differences in temperature of the steam as y it passes through the turbine is,-to a large degree, a measure of its energy content. The greater the difference in temperature the higher the order of energy. Unfortunately, the operating parts of the turbine subject to the flow of steam at the different temperatures encountered are prone to distortion under what is commonly referred to as thermal gradient. The term thermal gradient refers to a temperature difference across a single structural part or group of structural parts.

It is the object of this invention to provide a turbine construction in which the effect of stress due to thermal gradient is minimized.

It is further the object of this invention to provide a.

SUMMARY OF THE INVENTION The turbine construction forming the subject of this BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary view partially in section of a turbine equipped with the arrangement serving as the subject of this invention; and

FIGS. 2 and 3 are diagrammatic illustrations of a connection between a shroud ring and a partition with FIG. 2 indicating the arrangementv heretofore employed and FIG. 3 illustrating the arrangement serving as the subject of this invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring more particularly to the drawings, there is shown in FIG. 1 a fluid powered turbine utilizing a fluid such as steam, as a source of energy. The turbine V is of conventional construction to the extent that a barinvention involves a partition member connected with i the casing of the turbine which projects radially inwardly from the inner surface thereof. At its innermost radial extent the partition is provided with an axial ex- 7 rel type casing 11 is provided with an end closure 12 to form a housing for the operating parts of the turbine.

The barrel casing l I contains an opening 14 through which steam enters the turbine and flows via annular chamber 15 to a nozzle section 17 disposed at the bottom portion of the chamber 15. The casing 11 has extending from its inner surface, a partition 18, one surface 19 of which forms a part of the chamber 15 subject to high temperature, high pressure steam. The partition 18 includes a rearwardly extending section 20 disposed in an axial direction substantially parallel to the center line of the turbine. Section 20 terminates in a flange 22 as indicated in FIG. 1, while the construction illustrated reveals the partition 18 as integral with the casing, it is obvious the partition may be formed of separate parts, if desired.

Arranged in conventional fashion within the turbine casing is a rotor assembly 24 including shaft 26 having a plurality of spaced rotor blades 28 mounted about the outer surface thereof. The rotor blades 28 are circumferentially spaced and .include sealing elements 29 disposed at their outer ends. Shaft 26 is supported in spaced bearings, not shown, mounted in turn in the casing and end closure of the turbine. Appropriate sealing assemblies, conventional with machinery of the kind described are also employed but are not shown as a detailed description of them is not deemed necessary to an understanding of this invention. However, sealing ring 30 is shown disposed adjacent the casing 11 for preventing the escape of high temperature steam outwardly along the surface of the shaft 26.

A shroud assembly 32 is shown connected to the partition'18. The shroud assembly includes a shroud ring 34 having an axial section 36 projecting forwardly from a rear flange section 38. The shroud ring mounts a pinrality of spaced stator blades 40 which are interposed between the stages of the rotor blades 28 described above. Fastening means 40 connects the shroud assembly to the partition in the area wherein the flange members 22 and 38 abut one another. It will be noted that the forward surface of flange 38 engages the rearward surface of flange 22.

The shroud ring may be formed in a single piece or in a series of segmental pieces, depending upon the number of stages and/or configuration of the blading involved. It will be observed from a consideration of FIG. I that the shroud assembly may be inserted through the open end of the barrel casing. To facilitate such I assembly the shroud ring is provided with a stepped surface configuration of the kind illustrated in FIG. 1 wherein a radial clearance extends about the outer surface of the shroud ring 36 after it is assembled to the partition.

As indicated above, high temperature steam is introduced into chamber 15 and flows, via nozzle section 17, through the various stages of blading illustrated in FIG. I, to chamber 42 communicating with the outlet 16. The relatively high temperature steam is present in chamber 15 while the relatively low temperature steam is present in chamber 42. The surfaces of the parts connected by the fastening means 40 have a relatively low temperature surrounding same for the expansion of steam is substantially complete once the steam passes the rearmost stage of rotor blades 28, thus, relative distortion due to exposure to varying temperatures is maintained at a minimum. It will be obvious that the greatest temperature differential will occur across the radial portion of partition 18 where the material is of maximum thickness and thus, possesses maximum resistance to distortion.

In addition to the benefits derived involving minimum distortion as described above, the clearance 43 between the outer surface of shroud ring 34 and the inner surface of the partition provides space for the collection of a small amount of high pressure gas. The presence of this high pressure gas inhibits leakage that may occur along adjacent edges of abutting segments when the shroud ring is formed in segments.

To further illustrate the advantages of the construction here proposed, attention is directed to FIGS. 2 and 3. The prior art arrangement (FIG. 2) would involve high temperature steam at one or the lower side of the connecting fastener and low temperature steam on the other or upper side of the connecting fastener imposing a thermal gradient on the joint. FIG. 3, a duplicate of FIG. 1, removes the joint (connected flanges 22 and 38) from the area of contact with high temperature steam minimizing, if not completely eliminating, the effects of thermal gradient.

While a preferred embodiment of this invention has been described for purposes of illustration, it will be appreciated that this invention may be otherwise embodied within the scope of the following claims.

I claim:

1. A turbine comprising:

A. a casing serving as an enclosure for the operating parts of the turbine, said casing having an inlet and an outlet, said casing being provided with a radially inwardly projecting partition having an axially rearwardly extending section terminating in a radial flange,

B. a rotor assembly including a shaft having spaced regions supported in the casing, said rotor assembly including at least one row of circumferentially spaced blades arranged about the shaft so as to rotate therewith,

C. a shroud assembly encircling the rotor assembly, said shroud assembly including a shroud ring, at least one row of circumferentially spaced blades extending radially inwardly from the inner surface of the shroud ring, said shroud ring being provided with a radial flange having a forward surface in engagement with the rear surface of the casing partition flange, and a forwardly rojecting portion underlying e inwardly pro ec mg portion of the partition through substantially its entire length, and

D. means detachably securing the flange portions whereby the shroud ring is disposed with the blades thereof located axially adjacent the rotor blades.

2. A turbine as set forth in claim 1 wherein a small.

clearance is disposed between the shroud assembly and the casing partition; said clearance having communication with the inlet of the turbine. 

1. A turbine comprising: A. a casing serving as an enclosure for the operating parts of the turbine, said casing having an inlet and an outlet, said casing being provided with a radially inwardly projecting partition having an axially rearwardly extending section terminating in a radial flange, B. a rotor assembly including a shaft having spaced regions supported in the casing, said rotor assembly including at least one row of circumferentially spaced blades arranged about the shaft so as to rotate therewith, C. a shroud assembly encircling the rotor assembly, said shroud assembly including a shroud ring, at least one row of circumferentially spaced blades extending radially inwardly from the inner surface of the shroud ring, said shroud ring being provided with a radial flange having a forward surface in engagement with the rear surface of the casing partition flange, and a forwardly projecting portion underlying the inwardly projecting portion of the partition through substantially its entire length, and D. means detachably securing the flange portions whereby the shroud ring is disposed with the blades thereof located axially adjacent the rotor blades.
 2. A turbine as set forth in claim 1 wherein a small clearance is disposed between the shroud assembly and the casing partition; said clearance having communication with the inlet of the turbine. 